Asthma is a chronic inflammatory condition that causes the airways (bronchi) to produce excess mucus and close, making breathing difficult. Treatment has two main objectives: first, to control and reduce inflammation and, second, to reopen the airways. Drugs that achieve the first goal are called anti-inflammatory agents, and those that bring about the second are called bronchodilators. Many asthma sufferers inhale these medications.

Following are answers to a few commonly asked questions about dry-powder inhalers.

What Are the Advantages of Inhaling Asthma Medicines?

Anti-inflammatory treatment for asthma is long-term therapy. Often it is life long. Inhaling asthma medicine directly into airways and lungs has two advantages. First, the medicine goes directly to where it is needed and speeds relief of symptoms. And second, it limits the number of areas in the body exposed to the medicine and reduces the risk of side effects.

Are there Different Kinds of Inhalers?

Yes, there are three basic types. The first type is the Nebulizer. This is an electrical device that sends medicine directly into your mouth by tube or, in children, by clear mask. They require no hand-breath coordination. Simply put in the prescribed amount of medicine, take the tube in your mouth (or place the mask over the child's nose and mouth) and breathe normally until the medicine is gone.

The second type is the metered-doseaerosol. This sends a measured dose of medicine into your mouth using a small amount of pressurized gas. Sometimes a "spacer" is placed between the drug reservoir and your mouth to control the amount you inhale. Medicine is forced into the spacer, which you then squeeze as you inhale the medicine quickly. Aerosols fell out of favor a few years ago when the common propellant chlorofluorocarbon (CFC), a gas that depletes the atmosphere's ozone layer, was banned throughout the world.

The third type, the dry-powder inhaler, is a popular alternative to aerosols. It has the advantage of needing no propellant. But this is also a disadvantage. Because it has no propellant, it depends on the force of your inhalation to get medicine to your lungs. Children, people with severe asthma, and people suffering acute attacks may be unable to produce enough airflow to use dry-powder inhalers successfully. You can view a video of correct dry powder inhaler techniques at www.use-inhalers.com.

What Should I Expect from My Inhaler?

Inhaled anti-inflammatory drugs taken regularly should improve your breathing day and night, reducing the fear of having to struggle to breathe. They should reduce mucus production and, therefore, wheezing and coughing.

Inhaled bronchodilators will give you fast-acting, short-term relief from acute asthma symptoms caused by exercise or exposure to allergens if your asthma is mild to moderate.

What Kind of Side Effects Might I Experience?

In adults who use their inhalers only as prescribed, side effects are usually minor. Because the powder passes through your mouth on the way to your lungs, and because the particles are large, much of each dose (up to 90 percent) will deposit in your mouth or throat leaving a bad taste and perhaps irritating your tongue or throat. You can minimize this by rinsing your mouth after inhaling.

You may also swallow some of the medicine that remains after rinsing. This may cause minor stomach upset or "heartburn," which can do long-term damage. If it occurs, be sure to tell your doctor so it can be treated. Once absorbed in your stomach, swallowed asthma drugs are quickly eliminated from your body, so they don't have the widespread side effects of drugs taken as pills.

People with severe asthma who take larger doses of anti-inflammatory medicines may have more serious side effects. A common one is a mouth or throat infection with yeast, called oral thrush, which appears as a white coating on the lining of the mouth and throat. This is easily treated.

Mature women who, because of severe asthma, take large doses of anti-inflammatory drugs may have a more serious side effect. These drugs can accelerate osteoporosis (a bone disease) after menopause. This can be checked by measuring bone density and, if osteoporosis is present, it can be treated with drugs that stimulate bone formation.

Can My Child Use A Dry-Powder Inhaler?

Yes. Children five years old and up adjust easily to dry-powder inhalers, but they need careful instruction and watching to be certain they use them correctly. (Infants can use inhaled anti-inflammatory medicines by using nebulizers with masks.) Because of their low body weight, children's side effects are more dangerous for them than for adults. So despite the problems of teaching a child how to properly use an inhaler, this method of delivering medicine directly to the airways is preferred over pills for children.

As with adults, children with asthma may need more than one inhaler. In order to run, swim and play with others, a child with asthma may need one inhaler for constant anti-inflammatory treatment and another, containing different medicine, for bronchodilation when a child is involved in physical activity. This requires extra instruction from parents and the school nurse's awareness.

What Are the Side Effects in Children?

Even since anti-inflammatory therapy using corticosteroids was accepted as the front line treatment for asthma, including in children, researchers have debated its effect on growth. There is evidence that even low-dose, inhaled corticosteroids may temporarily delay a child's growth before puberty, slightly more in boys than in girls. After puberty, however, growth is regulated by sex hormones, and continued use of the steroid-based anti-inflammatory drugs has no additional impact. Ultimate height is not affected very much. Furthermore, the long-term benefits of these drugs greatly outweigh any minor effect on growth. Untreated asthma, in contrast, does cause reduction in final height.

There is newer evidence that anti-inflammatory medicines taken by dry-power inhaler may cause tooth erosion in children by changing the mouth's chemical environment. They also reduce the production of saliva, affecting the mouth's natural way of maintaining its chemical balance. To offset these side effects, some dentists recommend rinsing with a fluoride mouthwash and chewing sugarless gum to stimulate salivation after inhaling medicine. They recommend against brushing, because the action of brushing large-particle powder against young teeth may weaken already damaged enamel.

Who Should Use A Dry-Powder Inhaler?

Almost anyone with asthma (more than 90 percent of all asthma patients) is usually able to inhale enough air to make the inhalers operate properly. The dry-powder inhalers are currently the most common inhalers. However, infants and toddlers, and anyone unable to manage the minimum hand-breath coordination needed for effective use, should not use this method. It also excludes anyone who, for any reason, is not responsible enough to use the inhaler as it is prescribed. People with severe asthma, especially if confined to bed, may benefit more from the closed nebulizer system that provides constant airflow and uses smaller particles that get down to the airways more efficiently.

But if you take asthma medicines that are not available in inhalable form you must, of course, continue to depend on pills or injections.

Are Dry-Powder Inhalers Beneficial?

Yes. They are convenient and easy to use. They dispense medicine directly to the place where it is needed, greatly reducing side effects as compared with medicines taken as pills or tablets. They also deliver medicine to the troubled site quickly, without need for absorption, digestion and circulation. And they can deliver both long-lasting anti-inflammatory benefits or short-acting, quick-relief bronchodilation when needed. No other way of taking asthma drugs is so versatile.

Dry-powder inhalers are a delivery system. Complications of asthma therapy come mostly from the medicines themselves, not from the delivery systems. Yet the way the drug is delivered may influence how well it works and the number of side effects. Nevertheless, except in emergency situations or unusual complications, inhaling asthma drugs has more benefits than side effects compared to any other form of medicine delivery method.